Such a vacuum cleaner is disclosed for example, in EP-A1-1172059. In order to dampen noise from the motor/blower configuration of the vacuum cleaner, indentations with predetermined lengths are provided, which extend generally perpendicular to the noise propagation direction in an air flow passage. This arrangement requires that the depth of the indentations correspond to the frequencies of the generated noise. Such frequencies may however vary, for instance since the blower rotational speed may be changed by a varying load, thereby rendering the noise reduction difficult.
One problem associated with such vacuum cleaners is therefore to find alternative ways of reducing the emitted noise.